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The present invention involves a deviated viewing endoscope that has the advantage of all or part of the following options:
rotation of the viewing axis;
variation of the viewing angle;
rotation of the reticle; and
focusing control.
The term endoscope designates a rigid probe which, introduced into a lit cavity, makes it possible for the user to observe the inside of the cavity. In order to do this, an endoscope integrates by its nature, an optical device and a lighting device.
The term axial viewing endoscope designates an endoscope in which the optical axis of the distal lens is integrated with the mechanical axis of the endoscope. The optical device of an axial viewing endoscope comprises a frontal optical view port, a distal lens, a system for optical transport of an image generally comprised of a series of achromatic lenses and an ocular lens having a longitudinal displacement that makes it possible for the user to adjust the sharpness of the observed image. This optical device is calculated in a manner so that the image transmitted by the ocular lens does not have bi-directional inversion relative to reality. The lighting device of an axial viewing endoscope is comprised of a bundle of lighting fibers whose distal end generally comprises a lighting window in the form of a collar arranged around the frontal optical view port. The proximal end of the bundle of lighting fibers is housed in a lateral lighting seat integrated into the handle of the endoscope. The lighting field created by the distal lighting window covers the optical field of the endoscope when the lighting base is connected, by means of a lighting cable, to a light generator.
The term deviated viewing endoscope designates an endoscope in which the optical viewing axis forms an angle with the mechanical axis of the endoscope. The viewing is prograde if this angle is less than 90xc2x0, lateral if it is equal to 90xc2x0, and retrograde if it is greater than 90xc2x0. The optical device of a deviated viewing endoscope thus comprises in all cases a distal deviator prism.
If the distal prism is a deviator prism having total reflection characterized by a bi-directional inversion of the image transmitted by the prism, the optical device of the endoscope will comprise a lateral optical view port, the distal deviator prism, a lens, an optical system for transport of the image generally comprised of a series of achromatic lenses and an ocular lens whose longitudinal displacement makes it possible for the user to adjust the sharpness of the observed image. This optical system for transport of the image is calculated in a manner so that the image delivered by the ocular lens is not totally inverted relative to reality.
If the distal prism is a deviator prism having partial reflection characterized by a unidirectional inversion of the image transmitted by the prism, the optical device of the endoscope will comprise a lateral optical view port, the distal deviator prism, a lens, an optical system for the transport of an image generally comprised of a series of achromatic lenses, a correcting prism introducing a unidirectional inversion of the image transmitted by the prism and an ocular lens whose longitudinal displacement makes it possible for the user to adjust the sharpness of the observed image. The radial positioning of the correcting prism and the structure of the optical transport system is calculated in a manner so that the image delivered by the ocular lens is not partially inverted relative to reality. The deviated viewing endoscopes having adjustable focus equipped with a distal deviator prism having partial reflection have two main types of architecture. The first of these architectures involves endoscopes where the correcting prism is directly integrated into the optical system for transport of the image, the low dimensions of this correcting prism comprising a handicap in these conditions, as far as the luminosity is concerned. The second architecture mentioned appears for the first time in the patent dated 1938 (Louis K-PITMAN/U.S. Pat. No. 2,118,523/1938), and involves the endoscopes whose correcting prism comprises the proximal end of the optical device. In this case, it rapidly appeared as very advantageous to implement in the proximal part of the endoscope a cylindrical mount functioning to house the ocular lens, a mount whose proximal end shelters the correcting prism and whose distal end contains a field diaphragm (field stop) positioned in the distal focal plane of the ocular lens. The focusing control of the endoscope is done in longitudinally displacing this mount. This type of device, described since 1961 by the American company ACMI (U.S. Pat. No. 2,990,830/1961) has since been adopted by numerous endoscope manufacturers.
The lighting device of a deviated viewing endoscope is itself generally comprised of a bundle of lighting fibers whose distal end comprises a lateral lighting window located between the lateral optical view port and the distal end of the endoscope, the axis of lighting of this window being approximately parallel to the optical viewing axis of the endoscope. The proximal end of the bundle of fibers is housed in a lateral lighting seat integrated into the handle of the endoscope. The lighting field created by the lateral lighting window covers the optical field of the endoscope when the lighting seat is connected, by means of a lighting cable, to a light generator.
The problems of operation peculiar to customary deviated viewing endoscopes involve the panoramic exploration of the inside of a cavity. Such an examination actually requires the user to make the endoscope go through a rotation of 360xc2x0 around its mechanical axis, an operation that is rendered difficult by the presence of the lighting cable united with the lighting seat of the endoscope. These operational problems are the origin of the development of deviated distal xe2x80x9crotaryxe2x80x9d viewing endoscopes designated according to the manufacturers under the terms of xe2x80x9crotascopexe2x80x9d (HENKE SASS WOLF), of xe2x80x9cendoscope having a turning shellxe2x80x9d (EFER), of xe2x80x9cboroscope having a rotating light connectorxe2x80x9d (KARL STORZ), of xe2x80x9ctechnoscope having a rotary light connectorxe2x80x9d (RICHARD WOLF) or of xe2x80x9cborescope having orbital scanningxe2x80x9d (OLYMPUS). All of these endoscopes use a deviated distal endoscopic viewing probe whose proximal end turns to the inside from a handle equipped with a ring that controls the rotation of the probe, of a lateral seat for the connection of a lighting cable, a ring for adjusting the focus, and a proximal vision eye-piece cup. This type of architecture allows the user to make the endoscopic probe go through a rotation around its axis without changing the position of the lighting cable connected to the lateral lighting seat of the endoscope. The optical devices implemented in the different rotary endoscope models cited above can be classed in one of three families described in the following.
The first family of rotary endoscopes, developed numerous years ago notably by the German company HENKE-SASS WOLF, involves endoscopes having the optical device integrated in the rotating endoscopic probe and comprised of a distal deviator prism having total reflection, of a lens and of an optical system for transport of the image. The image delivered by the proximal end of the turning endoscope probe is transmitted to an ocular lens that is fixedly connected to a field diaphragm (field-stop) positioned in its distal focal plane and housed in a sliding manner in the handle of the endoscope, the longitudinal displacement of the ocular lens being controlled by an adjustment ring for focusing. The main disadvantage of the optical device described above results from the use of relatively expensive prisms having total reflection that are difficult to implement on a large scale of dimensions and deviation angles. The German company HENKE-SASS WOLF in 1989 described (German patent 0.371.233/1989) an original handle that makes it possible to improve the ergonomics of the controls of a rotary endoscope of this type.
The second family of rotary endoscopes, developed at the beginning of the 80""s notably by the French company EFER, involves endoscopes having the optical device integrated in the rotating endoscopic probe and comprised of a distal deviator prism having partial reflection, of a lens and of an optical system for transport of the image inside of which a correcting prism is inserted. The image delivered by the proximal end of the turning endoscope probe is transmitted to an ocular lens that is fixedly connected to a field diaphragm (field-stop) positioned in its distal focal plane and housed in a sliding manner in the handle of the endoscope, the longitudinal displacement of this ocular lens being controlled by an adjustment ring for focusing. The main disadvantage of the solution described above results from the fact that the low dimensions of the correcting prism integrated in the optical system for transport of the image of the rotating endoscopic probe limit the overall luminosity of the endoscope and in practice prohibit the implementation of such an optical device in endoscopic probes having a low diameter. One model of the endoscope of this type marketed at the end of the 90""s by the Japanese company OLYMPUS has nevertheless been described in a patent submitted in 1998 by the English company KEYMED (UK patent 2.322.944/1998).
The third family of rotary endoscopes involves endoscopes having the optical device integrated in the rotating endoscopic probe and comprised of a distal deviator prism having partial reflection, of a lens and of an optical system for transport of the image. The image delivered by the proximal end of the optical system for transport of the image integrated in the rotating endoscopic probe is transmitted to an ocular lens fixed in a mount housed in the handle of the endoscope, the ocular lens to which a correcting prism housed in the proximal end of the mount and a field diaphragm positioned in its distal focal plane are affixed. The proximal end of the rotating endoscopic probe is mechanically affixed to the mount in such a way that the distal deviator prism of the endoscopic probe and the correcting prism maintain the same relative alignment during a rotation of the probe around its axis. It is admittedly noted that the process consists in synchronizing the rotation of a deviator prism having partial reflection located at the distal end of an optical system with the rotation of a correcting prism located at the proximal end of the optical system has been described copiously in various patents involving the implementation of telescopes or periscopes (ERNST LEITZ GMBH/UK PATENT 1.272.742/1965, LUDWIG PIETZCH/GERMAN PATENT 28 33 944/1978, THEODOR PREUSSNER/UK PATENT 2.187.303/1987, THEODOR PREUSSNER/U.S. Pat. No. 4,787,725/1988). The synchronization of a distal deviator prism having partial reflection and a proximal correcting prism has also been implemented since 1977 in a distal deviated binocular rotary viewing endoscope described by JERRALD WIDRAN (U.S. Pat. No. 4,061,135/1977). In the case of a distal deviated rotary viewing endoscope, the device for correction of the direction of the image consists in coupling in rotation the endoscopic probe, and the mount that combines the field diaphragm, the ocular lens and the correcting prism must actually be connected to a focusing device that makes it possible to longitudinally move the mount relative to the proximal end of the endoscopic probe.
The process that falls within the public domain consists in connecting the proximal end of a rotating endoscopic sensor to a mount that combines a field diaphragm, an ocular lens, and a proximal correcting prism was implemented at the end of the 80""s by the German company RICHARD WOLF. The architecture adopted by this manufacturer is characterized by the structure of the handle of these endoscopes which have two distinct mechanical parts coupled in rotation: a distal xe2x80x9cfixedxe2x80x9d part that uses a ring for controlling the rotation and a lateral seat for connecting the lighting cable, and a proximal xe2x80x9crotatingxe2x80x9d part that uses an adjustment focusing ring that controls the longitudinal displacement of the mount that combines the field diaphragm, an ocular lens, and a correcting prism, where the mount is housed in a sliding manner inside the proximal part. The proximal end of the endoscopic probe, which rotates freely inside the distal part of the handle, is mechanically united with the proximal part of the handle. The German company KARL STORZ described in 1990 (U.S. Pat. No. 5,088,819/1992) an original handle that makes it possible to improve the ergonomics of the controls of a rotary endoscope of this type. The main disadvantage of the solution described above results from the fact that the rotation of the endoscopic probe leads to the rotation of the proximal part of the handle and thus the rotation of the eye-piece cup of the endoscope located in front of the user""s eye.
An original architecture that makes it possible to avoid this major disadvantage was implemented in 1992 by the French company EFER in the context of equipment for video thoracoscopy comprised of a rotary endoscopic probe having lateral sighting using a proximal focus control connected to a video camera. A similar architecture has been implemented in the deviated distal rotary viewing endoscopes marketed by the Japanese company OLYMPUS and described in the patents registered in 1993 by the English company KEYMED (UK PATENT GB 2 280 514, EUROPEAN PATENT EP 0 636 915, U.S. Pat. No. 5,540,650). A comparable architecture has also been described in a patent registered in 1998 by the French company TOKENDO (French patent FR 97 04569). All of the endoscopes relating to this type of architecture are characterized by specific mechanical coupling devices which the mount that combines the field diaphragm, the ocular lens and the correcting prism uses in advantageous way, whereby the mount is housed in a sliding manner and rotating inside the handle of these endoscopes. A first coupling device having a sliding nature makes it possible to transmit its rotational movement to the mount at the proximal end of the endoscopic probe, and regardless of the longitudinal position of the mount in the handle. A second coupling device makes it possible for the focus control ring to longitudinally displace the mount in the handle, regardless of the radial positioning of the mount in the handle. The solution described above, though notably improved in 2000 by the French company TOKENDO (French patent 98 12404) does not have any lower a number of serious disadvantages as a result of the mechanical tolerances that the complex kinematical devices connected to the mount that combines the field diaphragm, the ocular lens, and the correcting prism necessarily present, tolerances that lead to:
variations of the angular alignment between the distal deviator prism of the endoscopic probe and the correcting prism, variations manifested in random orientation defects of the image transmitted by the endoscope; and
variations in centering the correcting prism on the optical axis of the endoscope, variations manifested in random angular deviations of the output axis of the image transmitted by the endoscope.
The deviated distal rotary viewing endoscope and proximal focusing described in 2000 by the TOKENDO company (French patent FR 98 11826/ German patent DE 19942 152 A1/ U.S. Pat. No. 6,346,076/ British patent 2.342.462) has the advantage of an original opto-mechanical structure that makes it possible to eradicate definitively the mechanical alignment and centering defects mentioned above. The correcting prism of this endoscope is in fact permanently affixed in the proximal end of a cylindrical tube housed in a rotating manner in the handle of the endoscope and has its distal end that is united so that it is affixed to the proximal end of the rigid rotating endoscopic probe connected to this handle. The ocular lens of this endoscope and the field diaphragm connected to it is affixed in a cylindrical mount housed in a manner so that it slides in the median part of the cylindrical tube. A mechanical coupling device connected to an external ring for controlling the focus makes it possible to displace the mount longitudinally inside the cylindrical tube. The coupling device prevents any interference between the rotational movement of the cylindrical tube and the longitudinal translation movement inside of the tube of the mount of the ocular lens.
The different types of rigid rotary distal viewing endoscopes described above thus make easier the panoramic exploration of the inside of a cavity while allowing the user to turn the viewing axis of these endoscopes through 360xc2x0. Another category of rigid endoscopes offers a response to the same ergonomic problem: this involves endoscopes, generally called xe2x80x9cendoscopes having a dove prismxe2x80x9d whose user can make the optical viewing angle vary. The opto-mechanical devices implemented in such a context can fall under two different concepts.
The first of these concepts, described in 1987 in detail by the American company BAXTER (U.S. Pat. No. 4,697,577) involves endoscopes in which the rotation of the viewing axis in a plane parallel to the axis of the endoscopic probe is implemented by a distal deflection device comprised of two deviator prisms having partial reflection. The first of these prisms, fixedly connected to the distal end of the lens of the endoscope, introduces an optical deviation of 90xc2x0. This fixed prism is connected to a second mobile prism that also introduces a deviation of 90xc2x0 and is able to rotate around an axis perpendicular to the optical axis of the lens of the endoscope in a manner such that the optical input axis of the fixed prism and the optical axis of the mobile prism outlet are constant during the rotation of the mobile prism. Such an endoscope makes necessary a proximal correcting device that is comprised of two correcting prisms having partial reflection housed in the handle of the endoscope. The first of these prisms is a fixed prism designed to correct the unidirectional reflection introduced by the fixed prism of the distal deviation device. This fixed prism is connected to a second mobile prism rotating in synchronization with the mobile prism of the distal deviation device in a manner so as to permanently correct the unidirectional reflection introduced by the prism. A distal architecture similar to that mentioned above has been described in 1999 by the English company KEYMED (WO 0122865/2001). All of the endoscopes relating to the concept mentioned above have the advantage of a path of very sizeable variation of the viewing angle (on the order of 120xc2x0) making it possible to perform axial, prograde, lateral and retrograde observations. On the contrary, the intrinsic fragility of the distal optical view port specific to this type of endoscope makes their use in an industrial setting very marginal.
The second concept of an endoscope having a dove prism involves deviated viewing endoscopes in which the rotation of the viewing axis in a plane that contains the optical axis of the endoscopic probe implements a unique deviator prism having partial reflection housed in front of the distal end of the lens of the endoscope and able to turn around an axis perpendicular to the optical axis of the lens in a manner so that the optical axis of the output of the prism coincides with the optical axis of this lens. The optical device that makes it possible to correct the partial reflection introduced by the distal deviator prism can be in this case comprised of a simple prism correcting the partial reflection directly integrated into the optical system for the transport of the image from the endoscope according to a process described in 1965 by the French Atomic Energy Authority (UK PATENT 1.155.390/1966), process whose disadvantages as concerns luminosity have already been mentioned above. The proximal correcting and focusing device integrated into the handle of a bronchoscope designed in Russia and the object in 1963 of a patent registration in the USA (U.S. Pat. No. 3,096,756) comprises a more advantageous solution. This bronchoscope implements a cylindrical mount acting as housing for the ocular lens, the proximal end of which the correcting prism, and the distal end of which contains a field diaphragm fixedly positioned in the distal focal plane of the ocular lens. The focusing control of this bronchoscope is done by longitudinally displacing the mount. The path of the variation of the viewing angle of this type of endoscope, practically limited to approximately 70xc2x0, does not make possible axial observations. Their distal architecture makes it possible, on the contrary, to implement endoscopic probes having low diameters that are particularly robust.
It is rapidly appeared to be very interesting to improve the characteristics of a rigid deviated viewing endoscope by integrating simultaneously in the handle of the endoscope a proximal focusing device, a device for controlling the rotation of the viewing axis, and a device for controlling the tilting of the distal deviator prism. In 1998, the German company, KARL STORZ, described (WO 00/1199) a handle of a rigid deviated viewing endoscope integrating the three devices mentioned above. Although this document describes in a detailed manner the ergonomics of the handle, it does not provide, on the contrary, any information on the optical and mechanical mechanisms that make it possible to achieve this result. The only significant device described in this document involves the tilting of the distal deviation prism which is controlled by the longitudinal displacement of a metallic shaft arranged in parallel to the tube that functions for the housing of the optical system for transport of the image, the architecture having a cluttering that proves to be less favorable for the realization of endoscopes having low diameters.
A simple manner of estimating the dimensions of the surface defects of a mechanical part observed using an endoscope consists in positioning a reticle in the distal focal plane of the ocular lens of the endoscope. In these conditions, the image of this reticle is superposed on the observed endoscopic image by the user, and this even if a device for proximal focusing makes it possible to displace longitudinally a mount that integrates the ocular lens and the reticle. It thus appears of interest to offer to the user a simple method of xe2x80x9cmaking the reticle turn in the imagexe2x80x9d, this mechanism consisting simply in making the cylindrical mount turn around its axis in which the reticle and the ocular lens are housed. The document WO 99 56165 registered in 1998 by the English company KEYMED describes a deviated rigid viewing endoscope integrating simultaneously a device for rotation of the viewing axis, a device for proximal focusing, and a device for rotation of the reticle connected to the ocular lens of this endoscope. The area of application of the endoscope described in the document proves to be severely limited due to the integration of the correcting prism in the optical system for transport of the image, an arrangement for which the disadvantages as concerns the luminosity have been emphasized above several times.
The invention presented here has the purpose of describing a deviated distal viewing endoscope equipped with a partial distal reflecting prism and a proximal correcting prism having large dimensions, and able to integrate all or a part of the following devices:
rotational devices of the viewing axis;
devices for tilting the viewing axis;
device for proximal focusing; and
device for rotation of the reticle.
The present invention involves deviated endoscopes having rotating probes and distal sighting whose structure results from the connection of the devices described below.
1. A mechanical assembly that combines a cylindrical tubular handle and a rotating probe, the probe comprising a cylindrical internal tube connected affixed to an external metallic tube whose proximal end is united with a control ring surrounding in a rotating manner the distal end of the handle. The ring is also united with the distal end of a cylindrical tube housed in the handle and the proximal extension of the internal tube of the probe. The proximal end of the tube housed in the handle is surrounded by a cylindrical bearing arranged inside of the proximal end of the handle.
2. A stopper device designed to limit the range of rotation of the endoscopic probe.
3. An optical device comprised of a lateral view port integrated in the distal part of the external tube of the probe, a deviator prism having partial reflection, a lens housed in the distal part of the internal tube of the probe, an optical system for transport of the image housed in the internal tube, an ocular lens arranged in the tube housed in the handle and united with the rotating probe, a correcting prism for partial reflection housed in the proximal end of the tube and radially positioned in a manner so as to offset the unidirectional inversion of the image introduced by the distal deviating prism, and a transparent window housed in the proximal opening of the handle.
4. A lighting device comprised of a bundle of optical fibers housed in the annular volume comprised between the external and internal tubes of the rotating probe. The distal end of this bundle opens into one or more lighting windows arranged in the distal part of the external tube of the probe in a manner so that the lighting field covers the optical field of this probe. The proximal part of this bundle of fibers opens to the inside of the handle through a hole made in the tube housed in the handle and united with the rotating probe. The proximal end of this bundle of fibers is housed in the end of a lateral seat united with the handle and designed to be connected to the lighting cable. The proximal part of the bundle of fibers is coiled around the tube housed in the handle and united with the turning probe, this in order to prevent the rotation of the probe from causing the stresses able to break the fibers of this bundle.
5. Several independent mechanical devices each having a control ring surrounding the handle, where the rotation of the ring causes the longitudinal displacement of a cylindrical mount inside the tube housed in the handle and united with the turning probe. The kinematical structure of these devices prevents any interaction between the rotational movement of the probe and the translational movements of the cylindrical mount and the rotation of its control ring.
The devices mentioned above make it possible to realize and to integrate in a deviated distal rotary viewing endoscope all or part of the functions described as an example in the following:
Focusing control: device making it possible to longitudinally displace a cylindrical mount acting as the housing of an ocular lens of the endoscope;
Control for the variation of the viewing: device making it possible to longitudinally displace a cylindrical mount comprising the proximal end of a maneuvering tube housed in a sliding manner around the internal tube of the probe. The longitudinal displacement of the distal end of the maneuvering tube controls the around an axis perpendicular to the probe of the distal deviating prism having partial reflection of the endoscope; and
Control of the rotation of the reticle: device that makes it possible to displace longitudinally a cylindrical mount that uses a radial cylindrical finger housed in a manner running in a helicoidal groove arranged in the distal part of a cylindrical tube whose proximal end functions to be housed in a transparent reticule positioned in the distal focal plane of the ocular lens of the endoscope.